JPS5912218A - Catalyst burner - Google Patents

Abstract

PURPOSE:To improve a combustion performance and enlarge a combustion zone, by a method wherein a shielding plate such as heat resisting metals is placed in front of the catalyst of a burner, and a liquid fuel evaporator is heated through reverse flow of waste gas from the catalyst into a gap between a combustion tube and an outer tube. CONSTITUTION:A catalyst 7 is placed at the inside of a cylindrical horizontal type combustion tube 6 made of a heat resisting metal or other materials, and an outer tube 25, which is provided with a shielding plate 27 made of a heat resisting metal with a gap provided between the outer periphery thereof and the shielding plate, is located in front of the catalyst. Further, a flow uniformalizing plate 12 for gas fuel havig pores 13 is located to uniformalize a fuel stream, and a liquid fuel evaporator 16 having a sheath heater 18 is connected to the rear of the combustion tube 6. A liquid fuel such as kerosene is evaporated and is fed to the catalyst 7 togetherwith a combustion air for catalyst combustion, and simultaneously, waste gas discharged from the catalyst 7 is caused to flow reversely through a gap between the combustion tube 6 and the outer tube 25 to heat the liquid fuel evaporator 16 from the outer periphery.

Description

Detailed Description of the Invention The present invention evaporates liquid fuel such as kerosene, supplies it to a catalyst together with combustion air, causes an oxidation reaction on the surface, and uses the generated heat for hot air blowers, etc. The invention relates to a catalytic combustor.

Conventionally, this type of catalytic combustor has a structure Ii As shown in FIG. 1, the hot exhaust gas that passes through the catalyst A2 in the combustion tube A1 does not return again. could not utilize the amount of heat it had. In addition, as shown in Figure 2, the combustion cylinder B3 is made of thick aluminum die-casting, and the amount of heat generated from the catalyst body is transferred to the aluminum die-casting, and the heat is transferred in the upstream direction of the fuel air flow, and the liquid fuel is evaporated. In order to urge
Alternatively, there were systems that used transferred heat to heat the supplied fuel gas. However, in the system shown in Fig. 2, the fuel vaporization section 4
The portion where the catalyst body B5 is located is far away, and the heat conduction of the combustion tube 3 alone is insufficient for the required amount of heat.

3 Vane The present invention solves these problems with conventional catalytic combustors.The hot airflow that has passed through the catalytic body is passed through the outside of the combustion tube in the opposite direction again, and the part where the liquid fuel is evaporated is directly combusted. The system uses exhaust heat to heat the system. This eliminates the need for a conventional heater for heating liquid fuel, or even if a heater is necessary, it can play an auxiliary role. In addition to vaporizing the gaseous fuel, by preheating the mixture of fuel and combustion air, it is possible to increase the oxidation ability on the catalyst body and have various benefits such as improving combustion performance and expanding the combustion area. .

An embodiment of the present invention will be described below with reference to FIG. 3. A catalyst body C7 is installed inside a horizontal cylindrical combustion cylinder C6 made of heat-resistant metal or ceramics. The catalyst body C7 is made of heat-resistant ceramics supporting various catalysts (noble metal catalysts such as PT and PA, or transition metal oxide catalysts such as Ni and Co), and has a cross section of 1 nicam or lattice shape. It consists of a cylindrical skeleton structure made of multi-layered thin walls, and a plurality of small holes A8 pass through it. A flashback prevention plate 11 having a small hole B10 smaller than the small hole A8 of the catalyst body C7 is installed on the back surface of the catalyst body C7 with a slight gap 9 opened therein.

Furthermore, a gaseous fuel rectifier plate 12 made of metal or heat-resistant inorganic material is placed upstream thereof, and has a structure in which small holes C13 are opened so that the separated airflow flows uniformly. Further, behind the gaseous fuel straightening plate 12, a diffusion plate 14 made of a plurality of punched metal sheets or wire mesh is placed to improve the mixing of fuel and air. An electrode 15 is installed between the flashback prevention plate 11 and the gaseous fuel straightening plate 12 for igniting the catalyst body at the initial stage of combustion. At the left end of the combustion tube C6, a liquid fuel vaporizer 16 made of aluminum die-casting is installed to vaporize the liquid fuel.
is connected. The inner surface of the liquid fuel vaporizer 16 is a vaporization surface 17 for vaporizing the liquid fuel, and a heater 18 is provided inside the vaporization surface 17 for heating the vaporization surface 17 in the early stage of combustion. embedded. liquid fuel vaporizer 1
A combustion air inlet 19, which is an inlet for feeding combustion air, is opened at the rear of the engine 6.

A motor (not shown) and a turbo fan (not shown) are installed behind the liquid fuel vaporizer 16 to feed combustion air and turn the liquid fuel into fine particles.

The main shaft 2Q of the motor extends forward, and the tip directly enters the combustion air inlet 19 opened at the bottom of the liquid fuel vaporizer 16, and the tip blows the liquid fuel as fine particles onto the vaporization surface 17. A liquid fuel atomization plate 21 serving as a reservoir and a fuel diffusion plate 22 for widely dispersing the atomized liquid fuel in the axial direction are connected. A truncated cone-shaped cone 23 is placed between the liquid fuel atomization plate 21 and the main shaft 20, and plays the role of smoothly guiding the liquid fuel to the liquid fuel atomization plate 21. Liquid fuel is supplied by an electromagnetic pump (not shown)
The liquid fuel passes through the liquid fuel introduction pipe 24 and reaches the surface of the cone 23. Further, an outer tube 26 covers the outside of the combustion tube C6, and part or all of the combustion exhaust gas passes between the combustion tube C6 and the outer tube 250 and is discharged to the outside from the exhaust hole 26. A shielding plate 27 is placed in front of the catalyst C7 to allow exhaust gas to flow backward. The shielding plate 27 does not have the small exhaust holes 28 in the case where part of the exhaust gas is allowed to flow back.

Next, the entire operation of the above configuration will be explained.

First, an electric current flows through the sheathed heater 18 embedded inside the liquid fuel vaporizer 16, and the liquid fuel vaporizer 16 is heated. Temperature at vaporization surface 17 is 250C to 300C
When the fuel reaches the point, the motor (not shown) starts to rotate, and after a few seconds, the electromagnetic pump (not shown) for feeding the liquid fuel starts to move, passing through the liquid fuel introduction pipe 24 and reaching the tip of the main shaft 2o. Flows along the side wall of the truncated cone 23 located,
Fine particles form from the edge of the liquid fuel atomization plate 21 and reach the vaporization surface 17.
blown away. The blown away fine particles are further spread in the axial direction by the liquid fuel diffusion plate 22 on the way, and the particles are further made finer.

These liquid fuel particles are heated and vaporized at the vaporization surface 177.
5 and is vaporized at that point. On the other hand, combustion air generated by a turbo fan (not shown) is supplied to combustion air inlet 1.
9 and enters the liquid fuel vaporizer 16 and is evaporated by the vaporization surface 17 together with the liquid fuel gas into the diffusion plate 1.
4 and the gaseous fuel straightening plate 12, oxidation heat is generated on the surface of the catalyst body 07.

When this combustor is ignited, the electrode 15 sparks and a small flame is formed at the outlet of the small hole C13 bored at 1° in the gaseous fuel baffle plate 12 (the supply of fuel and combustion air is reduced at the time of ignition). The catalyst body C7 is uniformly heated from the back side by the flame,
After reaching the temperature range in which the catalyst can be oxidized, the amount of fuel and combustion air is increased several times that of full ignition, or the fuel supply is temporarily stopped to shift to catalytic combustion. A part of the hot exhaust gas discharged by combustion is released to the outside from the exhaust hole 28 of the shielding plate 27, and the remaining part is released into the combustion tube 6.
The liquid fuel is heated from the outer surface of the liquid fuel vaporizer 16 all the way between the outer cylinder 25 and the outer cylinder 25, and is discharged to the outside from the exhaust hole 26.

Depending on the configuration of the combustor or the vaporization temperature of the liquid fuel, the small exhaust hole 28 of the shielding plate 27 may be eliminated, and all the exhaust gas is allowed to flow backward through the outside of the combustion tube C6, completely heating the liquid fuel vaporization tube, and then flowing through the exhaust hole 26. It may also be released to the outside.

The material used is alumina because the shielding plate receives the exhaust gas directly from the catalyst and is therefore exposed to considerably high temperatures (sometimes exceeding 1000C).

Mullite, cordierite, zirconia, zircon
It is better to use heat-resistant ceramics such as mullite or aluminum titanate.

A feature of the catalytic combustor according to the present invention is that in a catalytic combustor that uses liquid as fuel, there is no need to use an external heat source such as an electric heater as a means to evaporate the liquid fuel, and in steady combustion. This means that self-combustion can continue as it is. Moreover, even when the amount of combustion is small and the amount of heat obtained is small, only a small number of supplementary heaters are required, resulting in energy savings. (In addition, an external heater is required for the vane at the stage of fully heating the liquid fuel vaporizer in the early stage of combustion.) In addition, in conventional catalytic combustors, the area around the catalyst body easily radiates heat to the outside, while the central part The fuel passing through this area was likely to be incompletely combusted, and CO or unprocessed hydrocarbons were likely to be released. For this reason, stable combustion was extremely difficult, especially in the low-calorie combustion region, but by adopting the configuration of the catalytic combustor according to the present invention, heat radiation from the surroundings of the catalytic body itself is almost eliminated.
During steady combustion, the entire catalyst body was heated uniformly, ensuring a wide stable combustion range from low combustion to high combustion.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams showing the configuration of a conventional catalytic combustor;
FIG. 3 is a block diagram of an embodiment of a catalytic combustor according to the present invention. 6... Combustion cylinder C, 7... Catalyst body C11
6...Liquid fuel vaporizer, 25...Outer cylinder, 27...Shielding plate, 28...Exhaust small hole.

Claims (1)

[Scope of Claims] (1) A combustor that vaporizes liquid fuel such as kerosene and supplies it together with combustion air to a catalyst body for catalytic combustion to perform catalytic combustion, and the outer periphery of a combustion tube in which the catalyst body is installed. By placing the outer cylinder with a gap and placing a shielding plate made of heat-resistant metal or heat-resistant ceramic in front of the catalyst body, the hot gas discharged from the catalyst body is transferred to the combustion cylinder and the outer cylinder. A catalytic combustor that heats a liquid fuel vaporizer from its outer periphery by causing reverse flow through the gap between the two. (Sakaki) The catalytic combustor according to claim 1, wherein a small exhaust hole is provided in a part of the shielding plate, and a part of the exhaust gas flows out from the small exhaust hole. (3) Alumina is used as the material of the shielding plate. 2. The catalytic combustor according to claim 1, wherein the catalytic combustor is made of a heat-resistant ceramic such as mullite, cochineyerite, zirconia, zircon-mullite aluminum titanate, or the like.